Tube with projecting portion raised on tube surface

ABSTRACT

The technical problem of this invention is to laminate the outer layer onto a main body of a tube, wherein a projecting portion or portions are formed, while maintaining certain uniformity. The object of this invention is to provide the laminated tube and molded tube products comprising the laminated tube, which shows the decorative effect, derived from the laminated outer layer, and enables the user to identify the tube only by touch. The outer layer is laminated onto the main body of the tube. By changing the number, width, or shape of the projecting portions, it is possible to give the decorative effect and identifiable features to the laminated tube. The laminated tube can be used to mold tube products, such as tubular containers and pouch containers.

TECHNICAL FIELD

This invention relates to a tube having an outer layer laminated onto asubstrate layer and to molded products using this tube.

BACKGROUND ART

Conventionally, there are known those tubes of a laminated structure inwhich the outer layer is laminated onto the substrate layer. Theselaminated tubes usually have a structure in which the outer layer islaminated uniformly in the peripheral direction of the tubecross-section.

The molded products of a laminated structure, in which an outer layer islaminated onto the substrate layer, are obtained by, for example,co-extruding two different types of synthetic resins or cladding thesubstrate layer with the second layer. In this cladding method, thesubstrate layer has already been made into a tube, and is clad with thesecond layer by an ordinary extrusion-molding process.

On the other hand, the co-extrusion molding method utilizes a moldingdie that has two or more separate flow paths for the molten resins andlets these flow paths merge within the die. The molding die has such across-section that gives the shape of a resinous tube. Two types ofresins are molten and run through the respective flow paths. The twolayers are welded firmly to each other, and the laminated tube isextruded from the die exit in the cross-sectional shape of the die, andis left to cool.

The laminated tubes made by conventional co-extrusion molding processhas difficulty in preventing cuts in the outer layer to be laminatedonto the substrate layer and also in cladding the outer layer in theuniform thickness because each synthetic resin has a different softeningpoint and flow resistance. A technology for laminating the outer layeronto the substrate layer at a uniform thickness has been developed tosolve this problem.

In the cladding method, too, it is also difficult to clad the substratelayer with the outer layer at a uniform thickness because there is apressure difference generated in the resin inside the head of theextrusion-molding die. In order for this problem to be solved, atechnology has been developed to extrude the outer layer in a pipe shapefrom the molding die having a diameter larger than the outer diameter ofthe tubular substrate layer and to make the outer layer stick onto thesubstrate layer by sucking the outer layer from the nipple side of thedie exit under reduced pressure.

However, if the outer layer laminated onto the substrate layer has auniform thickness, the tube looks even and monotonous and lacks spice,thus giving no decorative effect. Furthermore, the tube cannot beidentified simply by touch.

Meanwhile, even in the case where the outer layer laminated onto thesubstrate layer has some irregularity in molding the laminated tube, itis necessary to produce the irregularity while maintaining certainuniformity if a high-class image is to be achieved in addition toaesthetic appearances.

Consequently, the technical problem of this invention is to laminate theouter layer onto the substrate layer that makes up the main body of thetube, wherein the outer layer is a projecting portion or portions whilemaintaining certain uniformity. The object of this invention is toprovide the tube and the molded tube products comprising the tube, whichshow the decorative effect derived from the projecting portion(s) andwhich enable the user to identify the tube by touch, too.

DISCLOSURE OF THE INVENTION

The means of carrying out the invention to solve the above-describedtechnical problem exists in the configuration that the tube is laminatedand that the outer layer laminated onto the substrate layer, which makesup the main body of the tube, comprises a projecting portion disposed inthe axial direction.

An outer layer being a linear projecting portion in the axial directionis laminated onto the substrate layer that makes up the main body of thetube. The linear projecting portion on the outer surface of the tubegives the tube the decorative quality that makes the tube lookattractive. It also becomes possible to distinguish the tube from othertubes simply by touching the projecting portion on the tube surface withfingers.

Even if a relatively soft outer-layer is disposed on the substratelayer, the thin wall of the tube deforms easily because of thedifference in thickness between the projecting portion and the tubewall. Therefore, the main body of the tube can be easily pressed flatalong the projecting portion on the outer layer. The tube contents canbe easily squeezed out of the molded tube product made of this laminatedtube.

The means of carrying out the invention includes that the substratelayer is flexible and that the outer layer is harder than the substratelayer.

The substrate layer that makes up the main body of the tube hasflexibility, and the projecting portion to be laminated on the substratelayer is harder than the substrate layer. Therefore, this projectingportion serves as the backbone of the main body of the tube, andmaintains the form of the tube stably.

The means of carrying out the invention includes that the projectingportion is disposed linearly in the axial direction.

There is provided the linear projecting portion, which is laminated ontothe main body of the tube. The tube can be pressed flat along thisprojecting portion that acts as the backbone of the tube. Thus, theprojecting portion serves as the guide when the tube is pressed flat.

The means of carrying out the invention includes that plural projectingportions are provided.

Plural projecting portions are formed in stripes on the main body of thetube. The stripes improve decorativeness of the tube. From the number ofstripes determined for the tube, the user can distinguish the tube fromother tubes simply by touch.

The means of carrying out the invention includes that the projectingportions are disposed axisymmetrically in the cross-sectional view.

The projecting portions are disposed axisymmetrically. The tube can bepressed flat along the axisymmetrical projecting portions, thus makingit convenient for the tube bottom to be sealed when tubular containersor pouch containers are molded. As another advantage, the projectingportions serve as the guide to press and flatten the tubular containeror pouch container so that the contents can be easily squeezed out ofthe tubular or pouch container made of this laminated tube.

The means of carrying out the invention is provided with the projectingportions that have different widths.

The projecting portions having different widths make the tube look veryattractive, and allow characters and the like to be printed on the widetypes of projecting portions.

The means of carrying out the invention includes a configuration inwhich even-numbered projecting portions are disposed at equal intervalson the laminated tube.

Because the projecting portions are disposed at equal intervals, astripe pattern is formed over the entire tube surface, and thedecorativeness of the tube is improved.

The means of carrying out the invention includes that the projectingportions give a graded effect caused by the change in the thickness ofthe projecting portions disposed on the laminated tube.

The tube has the improved decorativeness because of the graded effectcaused by the change in the thickness of the projecting portions.

The means of carrying out the invention includes that an aluminumlaminating material is used as the main body of the tube.

The main body of the tube comprises an aluminum laminating material, andthe projecting portion or portions are laminated onto this material. Theprojecting portion or portions serving as the backbone reinforce thealuminum laminated tube, and also improves the decorativeness.

The means of carrying out the invention includes that the substratelayer and the outer layer have different colors in the tube.

Not only tube irregularity but also additional colors improve thedecorativeness because the outer layer in a different color is laminatedonto the substrate layer.

The means of carrying out the invention includes that the projectingportion or portions are disposed spirally on the surface of the tube.

The means of carrying out the invention includes that the projectingportion or portions have a wave form on the surface of the tube.

The projecting portion or portions are formed in a spiral or wave form,which looks attractive visually and improves decorativeness of the tube.

The means of carrying out the invention includes the configuration thateach of the projecting portions has a different color.

The decorativeness of the tube is improved because each projectingportion has a different color and because the projecting portions inattractive colors form a stripe or a waveform pattern. For instance, allthe projecting portions may have a different color, or two or threecolors may be repeated alternately or for each group of three projectingportions. Plural colors may also be used at random for the projectingportions.

The means of carrying out the invention includes that the tube is cut toa predetermined length, with one end being flattened and sealed, and theother end being provided with a head portion comprising shoulder andneck.

The means of carrying out the invention includes that the tube is cut toa predetermined length and is molded into a tube product having bothends flattened and sealed.

The tube with added decorativeness can be used to mold an elaboratelydesigned tube products.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1( a) is a partially cut, side elevational view, and FIG. 1( b) isa cross-sectional view, of the tube in the first embodiment of thisinvention.

FIG. 2 is a cross-sectional view showing another example of the tubeshown in FIG. 1.

FIG. 3 is a cross-sectional view showing an example of the co-extrusionmolding die of this invention.

FIG. 4 is a vertical section showing an example of the cladding die ofthis invention.

FIG. 5( a) is a partially cut, side elevational view, and FIG. 5( b) isa cross-sectional view, of the tube in the second embodiment of thisinvention.

FIG. 6 is a side elevational view of the tubular container made by usingthe tube shown in FIG. 5.

FIG. 7( a) is a partially cut, side elevational view, and FIG. 7( b) isa cross-sectional view, of the tube in the third embodiment of thisinvention.

FIG. 8( a) is a partially cut, side elevational view, and FIG. 8( b) isa cross-sectional view, of the tube in the fourth embodiment of thisinvention.

FIG. 9( a) is a side elevational view, and FIG. 9( b) is across-sectional view, of the tubular container using the tube in thefifth embodiment of this invention.

FIG. 10 is a perspective view of the pouch container molded from thetube.

FIG. 11 is a perspective view showing another example of the pouchcontainer molded from the tube.

FIG. 12 is a vertical section of the tube in the sixth embodiment ofthis invention.

FIG. 13 is a partially cut, side elevational view of the tube in theseventh embodiment of this invention.

FIG. 14 is a partially cut, side elevational view of the tube in theeighth embodiment of this invention.

FIG. 15( a) is a side elevational view, and FIG. 15( b) is across-sectional view, of the tube in the ninth embodiment of thisinvention.

PREFERRED EMBODIMENTS OF THE INVENTION

This invention is further described with respect to preferredembodiments, now referring to the drawings, in which FIG. 1( a) is aside elevational view, and FIG. 1( b) is a cross-sectional view, of thetube 1 in the first embodiment of this invention.

As shown in FIGS. 1( a) and 1(b), the tube has a laminated structureincluding an outer layer 3 and a linear projecting portion 4 thatextends in the axial direction, each of which is laminated onto thecylindrical substrate layer 2 that makes up the main body of the tube.

The projecting portion 4 can be formed when the outer layer 3 islaminated onto only a part of the substrate layer 2. In addition, asshown in FIG. 2, the projecting portion 4 can also be formed by changingthe thickness of the laminated outer layer 3 at one point of thecross-section.

FIG. 3 is a sectional view showing schematically a system for theco-extrusion molding of the tube 1. This system has die 11, which isconnected to the first extruder and the second extruder (both of themnow shown). The first extruder supplies the die 11 with a molten resinfrom which the substrate layer 2 is molded. The second extruder suppliesthe die 11 with another molten resin from which the outer layer 3 ismolded.

The die 11 is connected to the first extruder by way of a circular path.A substrate layer resin path 13 is in a tubular shape and is connectedto this circular path. An outer layer resin path 14 is disposed at onepoint on the periphery of the substrate layer resin path 13. This outerlayer resin path 14 is connected to the second extruder by way of aresin discharge port 12. A mandrel 15 is disposed ahead of the exit ofthe die 11.

A molten resin is extruded by the first extruder, takes the shape of atube in the circular path, and flows through the substrate layer resinpath 13. Another molten resin is extruded by the second extruder, comesout of the resin discharge port 12, and flows into the outer layer resinpath 14.

In the die 11, the molten resin coming from the outer layer resin path14 adheres onto the surface of the tubular molten resin that flowsthrough the substrate layer resin path 13. In this way, the outer layer3 is adhered onto the surface of the tubular substrate layer 2 at athickness that is uniform in the axial direction. Thus, a projectingportion 4 is formed on the substrate layer 2, as shown in FIG. 5, on theouter layer 3, which is adhered to the substrate layer 2, as shown inFIG. 2.

Consequently, the laminated tube 1 having the projecting portion 4 onthe substrate layer 2 is extruded.

In FIG. 3, mandrel 15 stably retains the shape of the laminated tube 1comprising the combined substrate layer 2 and the outer layer 3 havingor consisting of a projecting portion 4 when the tube is pushed out ofthe die exit. The co-extrusion molding die also comprises a coolingsystem to cool down the laminated tube 1 that has been extruded from themolding die 11, a pulling system to pull the extruded laminated tube 1,and a cutting device to cut the laminated tube to a suitable lengthalthough these systems are not shown. The laminated tube 1 ismanufactured after it passes through the processes using these systems.

At that time, a synthetic resin is suitably selected so that thesubstrate layer 2 to be formed has flexibility. On the other hand,another synthetic resin is selected so that the outer layer 3 is harderthan the substrate layer 2.

The co-extrusion molding process such as described above makes itpossible to mold the laminated tube 1, in which the outer layer 3 havingor consisting of the projecting portion 4, axially uniform in thickness,is laminated onto the substrate layer 2.

The projecting portion 4 creates irregularity on the surface of thelaminated tube 1. This irregularity improves the decorativeness andmakes the tube 1 look attractive visually. If the substrate layer 2 andthe outer layer 3 have different colors, the projecting portion 4 on thesubstrate layer 2 can be clearly identified by its color, thus resultingin improved designing.

Since the projecting portion 4 can be identified simply by touch, it iseasy to distinguish the laminated tube 1 from other tubes.

FIG. 4 is a vertical section showing schematically a part of the moldingdie to mold the tube by the cladding method. As shown in FIG. 4, themolten resin to be used as the outer layer 3 is pushed by the extruderfrom the resin discharge port (not shown) and flows into the outer layerresin flow path 14 in the die 11.

The outer layer resin flows through the outer layer resin flow path 14and comes out of the die exit where the diameter becomes much largerthan the outer diameter of the tubular substrate layer 2. The circulardie exit has a space at one point so that the projecting portion 4 isformed. The outer layer 3 is suctioned under reduced pressure in thedirection shown by an arrow in FIG. 4. The already tubular main body 2is supported by the mandrel 15, and the outer layer 3 is put in tightcontact with the substrate layer 2. Thus, the substrate layer 2 is cladwith the outer layer 3 having or consisting of the projecting portion 4that is axially uniform in thickness.

For example, a flexible aluminum laminating material can be used as thealready tubular substrate layer 2. Then, the outer layer 3 may be madeof a synthetic resin material that is harder than the aluminumlaminating material from which the substrate layer 2 is made.

Thus, the cladding method can also be utilized to mold the tube 1, inwhich the the projecting portion 4, which extends axially, is laminatedon the substrate layer 2, as shown in FIG. 5, or on the outer layer 3,which is laminated on the substrate layer 2, as shown in FIG. 2.

In both of the co-extrusion molding method and the cladding method, theaxially disposed projecting portion 4 has a uniform thickness. Unlikeany surface defect, such a projecting portion 4 gives improveddecorativeness to the laminated tube and is also capable of achieving ahigh-class image.

By changing the shape of the exit of the die 11, it is possible tochange the number, width, or shape of the projecting portion 4 on thelaminated tube 1.

FIG. 5 are (a) a side elevational view, and (b) a cross-sectional view,of the tube 1 in the second embodiment of this invention wherein twoprojecting portions 4 are disposed axisymmetrically on the substratelayer 2.

The two projecting portions 4 disposed axisymmetrically on the substratelayer 2 enable the tube 1 to be pressed flat easily. A pair of theprojecting portions 4 is made of a harder material than the substratelayer 2, which makes up the main body of the tube, and these projectingportions 4 serve as the backbone for the substrate layer 2 made of aflexible material, as shown in FIG. 5. The tube 1 is thus pressed flatand sealed to form a molded tube product, such as a tubular container ora pouch container made of this tube 1.

FIG. 6 shows a tubular container 9, one of the tube products, obtainedby cutting the tube 1 of FIG. 5 to a certain length, flattening andsealing one end of the tube, and fitting a head 8 to the tube by meansof Thatcher method. This head 8 comprises shoulder 6 and neck 7. Thetube portion of the tubular container 9 can be pressed flat, with theaxisymmetrical projecting portions 4 serving as the guide. Therefore,the contents inside the tubular container 9 can be discharged easily.

FIG. 7 shows the tube 1 in the third embodiment of this inventionwherein the tube 1 is provided with four projecting portions 4, whichare disposed axisymmetrically. In this case, the tube 1 of thisembodiment is easily pressed flat because the groove portion 5 betweenthe two projecting portions 4 on each side is folded and thrust outward.

When the projecting portions 4 are formed by the outer layer 3 laminatedonto the substrate layer 2, a certain number of projecting portions 4can be designated for the specified contents to be filled in the tubularcontainer 9 or later-described pouch container molded from the tube 1.The user will be able to distinguish the contents inside the tubeproduct, simply by touching the tubular or pouch container 9 or 10.Therefore, this feature is convenient especially for the blind. It isalso convenient for the user with ordinary sight in using plural tubularor pouch containers 9 or 10 for different purposes.

FIG. 8 shows the tube 1 in the fourth embodiment of this inventionwherein the outer layer 3 on the substrate layer 2 has, positioned onit, projecting portions 4 having different widths. Plural projectingportions 4 of different widths improve visual attractiveness of thetube.

FIG. 9 shows a tubular container 9 using the tube 1 in the fifthembodiment of this invention, wherein the outer layer 3 laminated ontothe substrate layer 2 consists of an even number of strip-likeprojecting portions 4 disposed in equal intervals. Under theconfiguration that an even number of projecting portions 4 are disposedin equal intervals on the substrate layer that makes up the main body ofthe tube, the tube 1 has an up-and-down stripe pattern, which improvesthe decorativeness of the tube.

Since the projecting portions 4 are disposed in an even number and inequal intervals, naturally there is an even number of grooves 5 betweenthe projecting portions 4. In this configuration, the tube 1 can beeasily pressed flat, with the projecting portions 4 serving as theguide. This feature is convenient when the tubular container 9 or thepouch container 10 (See FIG. 10) is molded. Because the tubularcontainer 9 or the pouch container 10 can be squeezed and pressed flat,using the projecting portions as the guide, the contents can be forcedout smoothly from the tubular or pouch container 9 or 10, thus improvingcontainer handling.

As shown in FIGS. 10 and 11, the tube 1 can be used to mold the pouchcontainer 10. The tube 1 is cut to a certain length, pressed flat andsealed at one end. Then, after the container has been filled with thecontents, the other end is similarly pressed flat and sealed. There canbe obtained a pouch container 10 with both ends being flattened in thesame direction, as shown in FIG. 10, or there can be obtained anotherpouch container 11 with one end is in a direction orthogonal to theother end, as shown in FIG. 11.

FIG. 12 is a vertical section of the tube 1 in the sixth embodiment ofthis invention. As shown in FIG. 12, the tube 1 comprises the substratelayer 2 that makes up the main body of the tube. In this embodiment, theouter layer 3 laminated onto the substrate layer 2 has or consists ofthe projecting portions 4, the thickness of which is changing in theaxial direction. In the case of the co-extrusion molding method, thethickness of the outer layer 3 can be changed by changing periodicallythe extruding pressure for the outer layer 3. In the case of thecladding method, it can be changed by changing periodically the extentof suction under reduced pressure.

The outer layer 3 having or consisting of the projecting portions 4gives a graded effect caused by the change in the thickness. Thisgradation improves the decorativeness of the tube 1.

FIG. 13 shows the tube 1 in the seventh embodiment of this invention,wherein the projecting portions 4 has a waveform pattern. In addition tothe linear projecting portions, the waveform projecting portions 4 canbe obtained by moving the die 11 from side to side at a certain strokewhen the tube 1 is molded. The waveform pattern improves thedecorativeness and visual attractiveness of the tube 1.

FIG. 14 shows the tube 1 in the eighth embodiment of this inventionwherein spiral projecting portions 4 are formed. Not only the linear andwaveform projecting portions, but also the spiral projecting portions 4can be obtained by rotating the die 11 on its axis in a certain rotativedirection when the tube 1 is molded. The spiral pattern improves thedecorativeness and visual attractiveness of the tube 1.

FIG. 15 shows the tube 1 in the ninth embodiment of this inventionwherein each projecting portion 4 has a different color. As shown inFIG. 15, the projecting portions 4 of different colors give the tube 1colorful stripe or waveform patterns, which improve decorativeness anddesigning of the tube 1. Although FIG. 15 shows the projecting portions4 in two colors that are alternately disposed, the pattern need not belimited to this embodiment. The projecting portions 4 in plural colorscan be used, or each projecting portion 4 may have a different color.Plural colors can also be used at random for each projecting portion 4.

EFFECTS OF THE INVENTION

The outer layer and the linear projecting portion in the axialdirection, as shown in FIG. 2, is laminated on the substrate layer thatmakes up the main body of the tube, or the linear projecting portion inthe axial direction, as shown in FIG. 5, is laminated on the substratelayer that makes up the main body of the tube. The linear projectingportion on the outer surface of the tube gives the tube the decorativequality that makes the tube look attractive. It also becomes possible todistinguish the tube from other tubes simply by touch.

The outer layer and projecting portion are harder than the substratelayer, and are laminated on the flexible substrate layer that makes upthe main body of the tube, as shown in FIG. 2. Alternatively, theprojecting portion is harder than the substrate layer, and is laminatedon the flexible substrate layer that makes up the main body of the tube,as shown in FIG. 5. Therefore, this projecting portion serves as thesupport to the main body of the tube, and maintains the form of the tubestably.

There is provided the outer layer and a linear projecting portion on themain body of the tube, as shown in FIG. 2, or a linear projectingportion on the main body of the tube, as shown in FIG. 5. The tube canbe pressed flat easily along this projecting portion, which serves asthe guide.

Plural projecting portions are formed on the main body of the tube.These projecting portions improve decorativeness of the tube. When theprojecting portions are onto the substrate layer, a certain number ofprojecting portions can be designated for the specified contents withwhich the tubular container or the pouch container molded from thelaminated tube is filled. From the number of the projecting portions,the user will be able to distinguish the contents, e.g., inside thetubular container, simply by touching the container. This feature isconvenient especially for the blind. It is also convenient for the userwith ordinary sight in using plural tubular containers for differentpurposes.

Since the projecting portions are disposed axisymmetrically, the tubecan be pressed flat along the axisymmetrical projecting portions. Thetubular containers or the pouch containers are molded easily by cuttingthe laminated tube to a certain length and sealing one end of the tube.Also when the contents are squeezed out of the tubular or pouchcontainer, the projecting portions serve as the guide to press flat thetubular or pouch container. The contents, such as cream having certainviscosity, can be easily forced out of the tubular container or thepouch container, and the container handling is improved.

The projecting portions with different widths are formed on thesubstrate layer that makes up the main body of the tube. Theseprojecting portions improve decorativeness, and make the tube lookattractive, and allow characters to be printed on the wide areas.

The projecting portions are disposed at equal intervals on the substratelayer that makes up the main body of the tube. Since a stripe pattern isformed over the entire tube surface, the tube shows improveddecorativeness.

The outer layer is formed on the substrate layer, which makes up themain body of the tube, so as to give a graded effect caused by theprojecting portions. The tube has the improved decorativeness because ofthe gradation created by the projecting portions.

The main body of the tube comprises an aluminum laminating material, andthe outer layer having or consisting of a projecting portion or portionsare laminated onto this material. The projecting portion or portionsserve as the backbone and reinforce the aluminum laminated tube. Sincethe projecting portions are formed on the aluminum laminating materialhaving a metallic silver color, the tube has improved decorativeness,and shows a high-class image.

The outer layer having or consisting of the projecting portions islaminated onto the substrate layer that makes up the main body of thetube. Not only surface irregularity but also additional colors improvethe decorativeness because the outer layer has or consists of aprojecting portion or portions in a different color or colors that makeit easy to identify the tube clearly.

There can be formed waveform projecting portions on the substrate layerthat makes up the main body of the tube. There can be formed spiralprojecting portions. In addition to linear projecting portions, theprojecting portions in various patterns formed on the substrate layerserve to improve decorativeness and visual attractiveness of thelaminate tube.

The decorativeness of the tube is improved because each projectingportion has a different color and because the projecting portions ofattractive colors form a stripe or waveform pattern.

The tube with added decorativeness can be used to mold an elaboratelydesigned tubular container or pouch container.

1. A tube comprising: a cylinder-shaped substrate layer that makes up amain body of the tube; and a linear projecting portion that extendsstraight along an entire axial length of the tube in an axial direction,the linear projecting portion being positioned on an outer surface ofthe cylinder-shaped substrate layer, wherein an outer layer is laminatedon the cylinder-shaped substrate layer to form the tube; the linearprojecting portion that extends straight along the entire axial lengthof the tube in an axial direction is raised on the outer layer to form aconvex shape without concave portions on the outer layer; a thickness ofthe tube on either side of the linear projecting portion is equal, andless than a thickness of the tube at the position of the linearprojecting portion such that the tube is bendable and as a resultfoldable at portions to either side of the linear projecting portion;and the tube is cut to a given length, flattened and sealed at at leastone end.
 2. The tube according to claim 1, wherein the cylinder-shapedsubstrate layer is more flexible than the outer layer, which is harderthan the cylinder-shaped substrate layer.
 3. The tube according to claim1, wherein a plurality of linear projecting portions are raised on theouter layer.
 4. The tube according to claim 1, wherein a pair of linearprojecting portions is raised axisymmetrically on the outer layer in across-sectional view.
 5. The tube according to claim 3, wherein at leastsome of the plurality of linear projecting portions have differentwidths.
 6. The tube according to claim 3, wherein an even number of theplurality of linear projecting portions are positioned at equalintervals around the main body.
 7. The tube according to claim 1,wherein the outer layer gives a graded effect caused by a change inthickness of the outer layer.
 8. The tube according to claim 1, whereinthe cylinder-shaped substrate layer is made of an aluminum-laminatedmaterial.
 9. The tube according to claim 1, wherein the main body of thetube and the linear projecting portion have different colors.
 10. Thetube according to claim 3, wherein the plurality of linear projectingportions are spirally disposed.
 11. The tube according to claim 3,wherein the plurality of linear projecting portions have a wave form.12. The tube according to claim 3, wherein each projecting portion has adifferent color.
 13. The tube according to claim 1, wherein the tube isprovided with a head portion at one end, the head portion including ashoulder and a neck.
 14. The tube according to claim 1, wherein thelinear projecting portion serves as a backbone of the main body of thetube and stably maintains a form of the tube.
 15. The tube according toclaim 1, wherein the outer layer and the linear projecting portion aremade of the same material.